1. Field of the Invention
The present invention relates to a method for preparing a furan derivative from biomass, including step (1) of preparing 5-hydroxymethylfurfural by reacting biomass and a solid acid catalyst in butanol; and step (2) of preparing a furan derivative by reacting the butanol solution of 5-hydroxymethylfurfural, obtained in step (1), with a hydrogenation catalyst.
2. Description of the Related Art
With the pressing issues on the development of alternative energy sources due to high oil prices, energy security, and strengthened regulations on greenhouse gas emissions, biofuel as the next-generation fuel has been rapidly distributed. Biofuel is a sustainable energy source produced from biomass present in nature. Biomass is a fossil fuel, i.e., a useful alternative energy source that can overcome the depletion of fossil fuel i.e. carbon resources, and is a concept including all organic matters of organisms including as animals, plants, microorganisms, etc. The biomass materials include a variety of byproducts and wastes produced in agriculture and forestry including various kinds of animals and plants, food wastes, industrial wastes based on living organisms, and cultivated crops for the purpose of producing biofuels (energy crops). Additionally, biomass is a collective term referring to renewable carbon resources including starch-, cellulose-, saccharide-, and protein-wastes, organic city wastes, etc. These biomasses can be converted into biofuels in gas, liquid, and solid states by applying physical, chemical and biological techniques, and the biomass fuels have an advantage in that they are not depleted, unlike fossil fuels. Accordingly, the production of useful chemical industrial materials from biomass can provide a platform for a new sustainable green chemical industry, and in particular, the biochemical technology of converting saccharides, which can be supplied from plant resources, into various chemical materials are expected to be realized in the near future.
Dimethylfuran (hereinafter, DMF) has the properties of higher energy density and chemical stability compared to those of ethanol, and is not water-soluble and thus does not absorb moisture in the atmosphere, thus being expected as the next-generation biofuel (Energy Fuels, 2010, 24: 2891). Additionally, DMF is a promising compound derived from biomass that is expected to be used as a monomer for a PET polymer by a reaction with ethylene (ACS Catal., 2012, 2: 935).
DMF is an intermediate and can be produced from fructose through 5-hydroxymethylfurfural (hereinafter, HMF). Specifically, DMF can be prepared by hydrogenation of particular saccharides, i.e., HMF, produced by dehydration of fructose in the presence of various acid catalysts. In particular, fructose can be obtained from glucose, which is a cellulose-forming unit structure.
Dihydroxymethyl furan (hereinafter, DHMF, or 2,5-bis(hydroxymethyl)furan; 2,5-BHF) are materials being highlighted as a monomer for a biomass-derived polymer. DHMF can be also synthesized via hydrogenation using HMF, a dehydrate of fructose, as an intermediate.
However, HMF, which is produced as an intermediate during the process of preparing the furan derivatives, has low thermal and chemical stability in an aqueous solution and thus can be easily converted into low value-added compounds such as levulinic acid and humin, after being produced in a predetermined reaction condition. Additionally, HMF has a disadvantage in that it tends to be easily transformed during a distillation process due to its very high boiling point at ambient pressure. Accordingly, the separation of HMF, which is produced by dehydration reaction of fructose and has high reactivity, from a reaction system and its subsequent use as a reactant in the DMF production process is not efficient or economical.
Accordingly, for improving the process efficiency of preparing DMF or DHMF from fructose, a method of using a biphasic reaction system by performing a dehydration reaction of fructose with a HCl catalyst in an aqueous solution, and inhibiting a secondary reaction by rapidly transporting the produced HMF using an organic extractant thereby improving the production yield of HMF from fructose was recently suggested. In particular, the HMF extracted with an organic solvent is converted into DMF by a subsequent hydrogenation reaction performed using a noble catalyst such as a CuRu/C catalyst (Nature, 2007, 447: 982). However, the biphasic reaction system may also accompany problems, such as an increase in energy cost due to high reaction temperature (>180° C.), a decrease in yield due to the increase of side reactions (<60%), complexity of devices and operation processes for their embodiments, difficulty in the use of a solid acid catalyst according to the use of an excess amount of NaCl additive, corrosion of a reactor due to the use of a homogenous HCl catalyst and difficulty of recovering the catalyst, inactivation of a catalyst in a HMF hydrogenation reaction by the remaining Cl ions, etc. Additionally, the DMF conversion yield of the CuRu/C catalyst used in the HMF hydrogenation reaction is about 80%, and thus there is a requirement for the development of a catalyst to improve the yield of the hydrogenation reaction, etc.
In the process of producing furan derivatives, in which HMF is prepared by the dehydration reaction of fructose and subsequently the hydrogenation reaction is performed described above, the HMF yield accounts for the highest percentage, that is, the increase of the HMF yield by 20% results in cost reduction by about 16%, and the price and the lifetime of the CuRu/C catalyst, which is used for the subsequent hydrogenation reaction, also account for relatively high percentages (Chem. Eng. J., 2011, 169: 329).
Meanwhile, a technology of preparing HMF from cellulose using a homogenous catalyst such as a CuCl2/CrCl2 catalyst and an ionic liquid as a solvent has been studied (Chem. Rev., 2011, 111: 397). In this process, cellulose may be used as a feed for HMF preparation, however, it has disadvantages in that an ionic liquid, which is expensive, is required as a solvent and also that the recovery of a catalyst from the product is cumbersome and difficult due to use of catalyst in the same phase. Additionally, there is also an inconvenience in that an organic solvent extractant should be additionally used for the separation of the product, HMF.
Additionally, a method of preparing HMF with a high yield of more than 95% from fructose in DMSO using a heterogeneous catalyst was reported (Catal. Comm., 2009, 10: 1849). However, DMSO itself is harmful to human body and it is decomposed in a reaction condition thereby producing sulfur-containing byproducts, and thus it is impossible to employ the method in large-scale production.